The REGFLOW pressure regulator, connected to an Oxygen or medical Air cylinder, is used to regulate the gas pressure by supplying the operating outlet with a controlled and stable pressure below its supply pressure. The pressure of the compressed gas cylinder can be read on the pressure gauge of the device. Combined with an RTM3 flowmeter with floating ball, the REGFLOW pressure regulator enables to adjust and measure the flow of a gas that is to be delivered to patients through the respiratory tract from a gas cylinder. Fitted with a quick-release connector it also enables to supply a ventilator or any other medical device with gas. Two connection systems to the gas cylinder are available: Bullnose fitting: for large cylinders (> 4 litres in water or 0.8 m3), Yoke pin-index fitting: universal system for small cylinders (< 4 litres in water or 0.8 m3).